Re: [PATCH v2 0/4] timer: Improve itimers scalability

Ingo Molnar
2015-10-16T07:12:09Z

* Jason Low <jason.low@hpe.com> wrote:

> > > With this patch set (along with commit 1018016c706f mentioned above),
> > > the performance hit of itimers almost completely goes away on the
> > > 16 socket system.
> > >
> > > Jason Low (4):
> > > timer: Optimize fastpath_timer_check()
> > > timer: Check thread timers only when there are active thread timers
> > > timer: Convert cputimer->running to bool
> > > timer: Reduce unnecessary sighand lock contention
> > >
> > > include/linux/init_task.h | 3 +-
> > > include/linux/sched.h | 9 ++++--
> > > kernel/fork.c | 2 +-
> > > kernel/time/posix-cpu-timers.c | 63 ++++++++++++++++++++++++++++-----------
> > > 4 files changed, 54 insertions(+), 23 deletions(-)
> >
> > Is there some itimers benchmark that can be used to measure the effects of these
> > changes?
>
> Yes, we also wrote a micro benchmark which generates cache misses and measures
> the average cost of each cache miss (with itimers enabled). We used this while
> writing and testing patches, since it takes a bit longer to set up and run the
> database.

Mind posting it, so that people can stick it into a new 'perf bench timer'
subcommand, and/or reproduce your results with it?

Thanks,

Ingo